1. Field of the Invention
This invention generally relates to an information medium recognition device and more particularly to a device for recognizing an information medium such as a signature handwritten by a signer, which is inputted by performing what is called an online input operation by using a writing means connected to a terminal or the like.
2. Description of the Related Art
A conventional character recognition device for recognizing a character inputted by what is called an on-line input operation by using a writing means (e.g., a pen) connected to a terminal or the like has a configuration illustrated in FIG. 9.
Namely, in the online input type handwritten character recognition device 1 of FIG. 9, inputting data representing a handwritten character is performed online using a handwriting input portion 4 consisting of a pen (or penlike stylus) 2 and a graphics tablet (hereunder referred to simply as a tablet) 3 and the inputted data is then recognized. A practical operation will be described as follows. First, a writer or operator handwrites a character on the tablet 3 with the pen 2. Generally, there are frames 11 indicating the size of a character to be inputted and the position, at which the character should be inputted, on an input surface of the tablet 3. Thus, the writer should write a character within the frame 11.
When the writer handwrites a character on the tablet 3, continuous coordinate data representing continuous coordinates of a locus of the pen 2 and data indicating whether or not any character is written (namely, what is called pen touch information), which are obtained by utilizing the electromagnetic coupling between the pen 2 and the tablet 3, are outputted from the tablet 3. Then these data are inputted to a feature extraction portion 6 of the character recognition device 1 in which it is judged where the end of the continuous coordinate data corresponding to each character is.
When the continuous coordinate data corresponding to each character is discriminated by the feature extraction portion 6, character stroke coordinate sequence data stored in a dictionary portion 10 are compared with the continuous coordinate data, successively, in a comparison portion 7 of the character recognition device 1 provided in a recognition portion 9. This character stroke coordinate sequence data are data indicating, for instance, the relative position of each stroke, the order in which strokes composing each character is generated and the length and direction of each stroke (namely, each stroke vector).
Each inputted character is handwritten. Therefore, in this comparison processing effected in the comparison portion 9, there are few cases in which the continuous coordinate data corresponding to such a handwritten character is matched with the character stroke coordinate sequence data. Thus, the comparison portion 9 outputs character stroke coordinate sequence data having a smallest relative error (namely, a smallest difference from the continuous coordinate data to be compared therewith) as data representing a first candidate character. Thereafter, the portion 9 outputs character stroke coordinate sequence data representing a second candidate character, and stroke coordinate sequence data representing a third candidate character, serially.
When the recognition portion 7 thus outputs results of the recognition of each inputted character sequentially, an output portion 8 displays each of the results of the recognition. Then, the writer or operator selects one of the displayed first, second and third candidate characters as the character inputted by the handwriting input portion 4.
However, in a conventional character recognition device, objects to be recognized are characters which can be registered by what are called printing types. In contrast, in cases of handwritten characters such as signatures, there are differences in shape of each character among signers. Moreover, there are subtle differences among signatures written by a same person. Thus, character stroke coordinate sequence data corresponding to each of such characters cannot be uniquely set. Consequently, the conventional character recognition device has a drawback in that it is difficult to recognize handwritten characters.
Furthermore, in the conventional online input type character recognition device, as a result of being provided with the tablet 3, the size of each input character and the range in which each input character is written, are limited. Moreover, there are errors (or changes) in continuous coordinate data due to difference in a writing speed. Consequently, the online input type character recognition device has a drawback in that it is difficult to recognize characters such signatures, which are not registered as printing types and are generally written continuously. The present invention is accomplished to eliminate the above described drawbacks of the conventional device.
It is, accordingly, an object of the present invention to provide an information medium recognition device which can recognize an information medium such as a handwritten signature inputted by effecting what is called an online input operation.